Padparadscha, Retrocognisant

Retrocognition {u}{r} (You may tap this creature and
pay {u}{r}. If you do, reveal and tap each creature
that was placed face down this turn.)

{w}{u}{b}{r}{g}, {t}: Exile this creature and another
target nontoken gem creature you control. Create a
creature token that has the combined colors, creature
types, power, toughness and keyword abilities of the
exiled creatures. Return the exiled cards to their
owners control when the token leaves the battlefield.
Activate only as a sorce